Pneumatic hammer.



v PATENTED APR. 5, 1904.

E. GUNNELL. PNEUMATIG HAMMER.

APPLIGATION FILED DEO. 17, 1900.

N0 MODEL.

n il. ill.

ivo. 756,35v.

UNITED STATES 1atented. April 5, 1904i.

PATENT OFFICE.

ELIAS GUNNELL, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO W. I.BABCOCK, OF CHICAGO, ILLINOIS.

PNEUMATIC HAMMER.

SPECIFICATION forming part of Letters Patent No. 756,357, dated April 5,1904.

Application filed December 17, 1900. Serial No. 40,078. (No model.)

ATo all wlwwt'it may concern,-

Be it known that I, ELIAS GUNNELL,a citizen of the United States,residing at Chicago, in the county of Cook, in the State of Illinois',have invented a certain new and useful Improvement in Pneumatic Hammers,of which the following is a description, reference being had to theaccompanying drawings, forming stant pressure, by the pressure of motiveiuid intermittently admitted to its superior forward end or pressurearea; while other features of my present invention are applicable toother types of tools, all as will be hereinafter more fully explained.

In the accompanying drawings, Figure lis a vertical longitudinal sectionof my hammer, with the piston in rearward position, and with thethrottlecvalve controlling the admission of motive iiuid to the toolclosed; Figure 2, a corresponding view with the throttle valve open,andwith the piston driven to the forward limit of its stroke; Figure 3, acorresponding view illustrating a modified construction; and Figures 4.and 5 sectional details showing the split spring rings for holding theworking tool in place.

The same letters of reference are used to indicate identical parts inthe several views.

The cylindrical body of the tool is in Figures 1 and 2 composed of aninner cylinder A, a surrounding sleeve B, and an outer casing C, thelatter having formed upon the under side of its rear end a suitablecasting D for the throttle valve chamber and for the connection of themotive fluid supply-pipe, and upon the upper side of its rear end acurved arm E to which the upper end of the grasping handle F is hingedat a. The sleeve B is conned in the casing C (with its front endabutting against the front wall of the internal bore of said casing) bythe inner cylinder A which .is provided with an annular shoulder at andthe inner cylinder A is itself confined in the casing C by a screw-plugG screwed into the rear end of the casing C and abutting at its forwardend against the rear end of the cylinder A. The plug G is provided witha peripheral flange c having ratchet teeth with which co-operates aspring catch d to hold the plug in the position to which it is turned.

The cylinder A is bored out to two different diameters to receive thepiston composed of the enlarged front end or head H and rearwardlyextending stem or body I, and at its forward end terminates short of thefront end of the sleeve B to'form a chamber for the cylindrical valve J.The front end of the sleeve. B is thickened interiorly, therebycontracting its internal bore, 'and in this contracted portion of thesleeve lits the forward portion or body of the cylindrical valve J,while the rear end of the valve is, provided with an exterior annularenlargement or flange which fits and travels in the main bore of thesleeve B in front of the cylinder A, and is provided with a beveledsurface as shown to co-operate with theseat formed for it by the frontend of the cylinder A.

The front end of the casing C isprovided with a reduced central bore andbushing K, through which the shank of the rivet set or other workingtool L passes and projects into the interior of the cylinder or frontend of the piston chamber, within the valve J.

A long passage M terminates at its forward end in a port e extendingthrough the thickened portion of the front end of the sleeve B,

and communicates at its rear end bya port f with the reduced rearportionofthe piston chamber. When the valve J is in forward position, shownFigure l, and the piston in its rearward position, there shown, the porte' lis closed by the valve J and the port f by the 4 ward end of thepiston chamber or internal bore of the cylinder, occupied by the valveJ.

The forward portion of the cylinderA is provided upon its exterior withlongitudinal grooves e' communicating at their rear ends with theinterior of the cylinder by ports j, and the sleeve B and casing* C areprovided in front of the cylinder A with exhaust ports O, which are openwhen the valve is in forward position, as in Fig'ure l, but Closed whenthe valve is in rearward position, as in Figure 2. Other exhaust portsor openings I?, extending through the cylinder A, sleeve B, and casing Cat the rear end of the larger portion of the piston chamber, permitingress and egress of air behind the head of the piston in thereciprocations of the latter.

The rear end of the cylinder A and screwplug Gr are bored out to form anenlarged chamber Q to which the motive fluid is constantly admitted whenthe tool is in operation through a circular row of ports 7c connectingit with a surrounding annular chamber 7c into which opens the main inletpassage controlled by the throttle valve located in the casting D andhereinafter described.,

In the position of the parts shown in Figure l the portion of the pistonchamber in front of the piston is open to the exhaust through the portsO, and the piston will therefore be driven forward by the pressure ofthe motive fluid admitted to the chamber Q when the throttle valve isopen. As the piston reaches the forward limit of stroke its head H willenter the valve J and contact with the shank of the tool L, and its rearend will simultaneously uncover the port g and permit the motive fluidbehind the piston to pass forward through a passage N to the front endof the piston chamber and there act upon the front end of thecylindrical valve J and drive the latter rearward to the position shownin Figure 2, causing the beveled surface of its rear end to seat itselfagainst the front end ofthe cylinder A and cut ofi' communicationbetween the exhaust ports O and the interior of the cylinder. Thisrearward movement of the valve J will also uncover the port e, so thatmotive iiuid will pass forward through both of the passages M and N tothe front end of the piston chamber and act upon the head H of thepiston and drive the latter rearward.

As soon as it has moved rearward far enough for its stem I to close theportf the admission of live air to the front end of the piston chamberwill be cut off, and the further rearward movement of the piston will beeffected by the expansion of the live air previously admitted and theacquired momentum of the piston. Vhen the piston reaches the rearwardposition shown in Figure l and uncovers the ports y' the pressure withinthe piston chamber which has driven the piston rearward will passthrough said ports and the grooves or passages/a' to the rear end of thevalve J, and there acting upon a pressure area superior to that of thefront end of the valve will drive the latter forward and uncover theports O, permitting the pressure in front of the piston to escape andthe piston to be driven forward again after its momentum has been ar.rested by the pressure behind it in the chamber Q.

In the particular construction shown in my former patent heretoforereferred to the valve J was given its rearward movement by pressureconstantly admitted to its forward pressure area through a long passageextending rearward through the cylinder wall and in constantcommunication with the pressure supply, and was driven forward bypressure intermittently admitted to its preponderating rearward pressurearea. Under my present construction the valve is shifted in eachdirection by intermittently admitted pressure, and the constant pressuresupply -passage mentioned is dispensed with. In both instances, however,the valve serves to control both the inlet and exhaust of the motivefluid at the front end of the piston chamber, but this is not essential,since in Figure 3 of my present drawings I have illustrated a valvewhich operates to control only the exhaust, the admission of the motivefluid being controlled by the piston itself.

In the construction shown in Figure 3 I provide a reservoir chamberRinthe cylinder A, which communicates with the smaller bore of the pistonchamber by ports 6, and by ports g with the passages N leading to thefront end of the pistonchamber as in Figures l and 2. No passagecorresponding to the passage M and having its front end controlled bythe valve J is employed. As the piston reaches the forward end of itsstroke and its head H enters the valve J and contacts with the shank ofthe tool L, its rear endl will uncover the ports g and admit the motiveiluid to the chamber R and passages N, and thence to the front end ofthe piston chamber where it will operate to shift the valve J rearward,to the po sition shown in Figure 2, thereby cutting olf communicationbetween the exhaust ports O and the interior of the piston chamber, andalso serves to drive the piston rearward. The rear end of the stem I ofthe piston will cover and close the ports g at the beginning' of itsrearward movement but the expansive pressure of the extra supply ofmotive fiuid in the reservoir chamber R, aiding that in the pistonchamber, will serve to drive the piston on rearward, against the fullpressure acting upon its smaller' rear end, until the head of the pistonpasses rearward of and uncovers the ports y', thereby admitting'pressure through the passages e' to the rear pressure area of the valveJ, as in Figures l and 2, and driving' the latter forward again andopening' the exhaust ports O, to permit another forward stroke of thepiston.

IOC

The passage 7c through which the motive fluid is admitted from thesupply pipe to the chamber Q is controlled by a balanced throttle valveS of familiar spool form fitting in a sleeve or bushing T driven in abore in the casting D. The forward head ofthe valve controls the portsmr in the sleeve T, which aord communication between the interiorthereof and a chamber U formed in the casting D around the sleeve T andcommunicating with the main inlet V to which the supply-pipe isconnected, and the interior of the sleeve T communicates by a port nwith the passage 7c leading to the chamber Q. A strong coiled spring Wlocated in the front end of the sleeve or bushing T and acting againstthe forward head of the valve presses the latter rearwardly and tends tohold it in the position shown in Figure l, with `its forward headclosing the ports m and cutting off the supply of motive fluid to thetool.

The handle F, which, as heretofore described, is hinged at its upper endat a to the arm E projecting upwardly and rearwardly from the rear endof the cylinder, has tightly driven into a suitable bore in its lowerend a forwardly extending rod or pin Xwhose front end is adaptedftoContact with the rearwardly projecting'stem of the throttle valve S,whereby pressure upon the handle F, when the work ing tool L is pressedagainst the rivet or other work, willforce the valve S forward in itschamber, against the resistance of the spring W, and open the ports mand admit motive fluid to the tool.

The arm E to which Vthe upper end of the handle is hinged extendsrearwardly, beyond the pivot a, to the dotted line a', and the handle isprovided with a corresponding slot to receive and embrace thisrearwardly project- .ing end of the arm E. The rear wall of this slot isindicated by the dotted line b', Fig. 2, and its contact with the rearend a of the arm E limits the swinging movement of the handle F upon itspivot a, and consequently limits the rearward movement of the valve Sunder the stress of the spring W. For the purpose of adjustably limitingthe forward movement ofA the lower end of the handle, and consequentlyregulating the opening movement of the valve S, the forwardly projectinglower end of the handle F is interiorly threaded to receive a nut Ywhich is provided upon its front end with an outwardly projecting flangeZ which lits between the forward end of the handle and the rear side ofthe casting D containing the valve chamber and valve and contacts withsaid casting to limit the forward movement'of the lower end of thehandle and consequent opening movement of the valve when pressure isapplied to the handle. By turning this nut in one direction or the otherthe movement of the handle and degree of opening of the valve effectedthereby may be regulated as desired. The flange Z of the nut cgi has amilled exterior to enable it to be readily turned by the operator toeffect the desired adjustment.

The spring W is preferably of such strength as to be overcome, and thevalve permitted to be opened, only by pressure upon the handlesufficient to hold the tool up to its work, so that no inadvertent oraccidental opening of the valve is liable to occur. Instead of thespring W the valve may be constantly pressed rearward by motive fluidadmitted to a closed chamber in front of the forward head of the valvethrough a minute passage or leak constantly communicating with the maininlet V.

In the construction shown in Figure 3 the casting D, cylinder headG andcurved arm or handle support E are formed integrallywith each other andseparate from the cylindrical body or casingof the tool and screwed uponthe rear end of the latter, being provided with an interiorly threaded,forwardly projecting sleeve E adapted to receive the exteriorly Ythreaded rear end of the cylinder or casing. The inner cylinder A is inthis instance provided upon its rear end with a circumferential flangewhich .is clamped between the rear end of the casing C and cylinder headGr when the latter is screwed into position upon the rear end of thetool. The outer casing or cylinder of the tool is provided with acircumferential flange C provided upon its rear face with ratchet teethwith which co-operates a spring catch C to keep the parts from becomingunscrewed. The remainder of the construction is substantially thesame asin Figures l and 2,' vexcepting that the inlet passage It opens directlyinto the rear end of the piston chamber behind the piston, instead ofopening into an enlarged chamber Q, as in Figures 1 and 2.

I am aware that it isnot broadly new to control the throttle valve ofpneumatic ltools by pressurel applied to the tool or the handle thereofin holding it up to its wor-k; but I believe I have produced a simplerand more eilicient construction than those heretofore employed, and onein which the advantage of a large and direct inlet for the motive fluid,controlled by the throttle valve, is attained to a greater degreethanheretofore.

In the present instance the rivet set L or other working tool isremovably held in povsition in the front end of the cylinder by means ofa 4split spring ring K fitting inl an annular chamber I formed for it inthe bushing K and surrounding and frictionally engaging the shank of thetool L, Figures 4 and In assembling the parts the ring K is compressedsufficiently to permit its insertion through the bore of the bushing Kuntil it comes opposite the recess or chamber K, whereupon it springsoutward into said recess. Upon then inserting the shank of the tool Land forcing it rearward its rear end will slightly expand the ring K andthe shank of the tool will pass on through the ring until it IOO TIO

reaches its innermost position. The frictional grip of the ring upon theshank of the tool will prevent any accidental displacement of thelatter. For the purpose of preventing the working tool being forciblyexpelled by any inadvertent blow of the piston when the tool is not heldup to its work I make the recess K in Figure 5 taperingin form, andprovide a corresponding beveled ring K. rlhis ring frictionally gripsthe shank of the working tool and prevents its accidental displacement,as does the ring K in Figure 4; but if the working tool be forciblydriven forward by the piston when not pressed against the work thebeveled ring K' in Figure 5, moving' forward with the shank of the tooland engaging the beveled or tapering wall of the recess K", will bewedged inward and compressed upon the shank of the tool and so firmlygrip the latter as to prevent its further forward movement.

In either case the working tool may be readily removed by giving it atwisting movement and steadily pulling it outward, and can be reinsertedin the manner before explained.

Having thus fully described my invention, I claim- 1. In a pneumatichammer, the combination, with the cylinder and the throttle valvecontrolling the admission of the motive fiuid thereto, of a hingedgrasping handle co-operating with said valve to open the same when thetool is held up to its work by pressure applied to said handle.

2. In apneumatichammer, the combination, with the cylinder and thethrottle valve controlling the admission of the motive iiuid thereto, ofa grasping handle hinged at one end to one side of the tool at its rearend and co-operating at its opposite free end with the throttle valve atthe opposite side of the tool to open said valve when the tool is heldup to its work by pressure applied to said handle.

3. In apneumatichammer, the combination, with the cylinder or body ofthe tool provided at one side of its rear end with an outwardlyprojecting arm or handle-support, and at its opposite side with acasting containing a throttle valve chamber, a throttle valve located insaid chamber and controlling the admission of the motive fluid to thecylinder, and a grasping handle hinged at one end to the arm orhandle-support and co-operating at its opposite free end with thethrottle valve to open the same when the tool is held up to its work bypressure applied to said handle.

4. In a pneumatic hammer, the combination, with the cylinder and thethrottle valve controlling the admission of the motive fluid thereto, ofahinged grasping handle co-operating with said Vvalve to open the samewhen the tool is held up to its work by pressure applied to said handle,and means for regulating the extent of such opening of the valve by saidhandle.

5. In a pneumatic hammer, the combination, with the cylinder and thethrottle valve controlling the admission of the motive fluid thereto, ofahinged grasping handle co-operating with said valve to open the samewhen the tool is held up to its work by pressure applied to said handle,and an adjustable stop or contact device interposed between the handleand cylinder or fixed part thereof to limit the movement of the handlein opening the valve.

6. In apneumatic hammer, the combination, with the cylinder and thethrottle valve controlling the admission of the motive fluid thereto, ofa grasping handle hinged at one end to the rear end of the cylinder orbody of the tool at one side thereof', and co-operating at its oppositefree end with the throttle valve on the opposite side of the tool toopen the same by pressure applied to the handle, and an adjustable stopor contact piece interposed between the free end of the handle and thecylinder or fixed part thereof to limit the movement of the free end ofthe handle in opening the valve.

7. In a pneumatic hammer,the combination, with the cylinder and thethrottle valve controlling' the admission ofthe motive fluid thereto, ofa grasping handle hinged at one end to the rear end of the cylinder orbody of the tool at one side thereof, and co-operating at its op--posite'free end with the throttle valve on the opposite side of thecylinder to open the same by pressure applied to the handle, and anadjustable nut interposed between the free end of the handle and thecylinder or a fixed part thereof to limit the movement of the handle inopening the valve.

8. In a pneumatic hammer, the combination of the cylinder provided uponone side of its rear end with the arm or handle-support E and upon theopposite side thereof with the casting D containing the throttle valvechamber, the valve S located in said chamber and controlling theadmission of the motive fluid to the cylinder, the grasping handle Fhinged at one end to the arm E and co-operating at its opposite free endwith the valve S to open the same when the tool is held up to its workby pressure applied to said handle.

9. In a pneumatic hammer, the combination of the cylinder provided uponone side of its rear end with the projecting arm or handle-support E,and upon the opposite side thereof with the casting D containing thethrottle valve chamber, the throttle valve S located in said chamber andcontrolling the admission of the motive fluid to the cylinder, and thegrasping handle F hinged at one end to the arm E and provided with ashoulder or contact surface 7) co-operating with the like shoulder orcontact surface c upon the arm E, and co-operating at its opposite freeend with the throttle-valve S to open the same.

10. In a pneumatic hammer, the combination IUO IIO

of the cylinder provided upon one side of its rear end with theprojecting arm or handlesupport E and upon the opposite side thereofWith the casting D containing the throttle valve chamber, lthe valve Sin said chamber controlling the admission of the motive fluid to thecylinder, and the grasping handle F hinged at its upper end to the arm Eand provided at itslower end With the pin or rod X co-operating With thevalve S.

ll. 1n a pneumatic hammer,the combination of the cylinder provided uponone side of its rear end With the projecting arm or handlesupport E andupon the opposite side thereoil With the casting D containing thethrottle valve chamber, the valve S in said chamber controlling theadmission of the motive iuid to the cylinder, the grasping handle Fhinged at one end to the arm E and provided at its opposite end With thepin or rod X co-operating With the valve S, and the tubular regulatngnut screwed into the free end of the handle F and provided With theflange Z in'- terposed between said handle and the cast# ing D.

ELIAS GUNNELL.

Witnesses:

YEDWARD RECTOR,

J oHNl H. BERKSTRESSER.

